a little neanderthal ass. >> one view is wement the other species out. but it looks more complicated than that. and it wasn't a complete wipeout as we've learned in the last couple of years. >> stephen: what do you mean? there are no neanderthals left. >> they were into interbreeding. >> stephen: come ocome on. >> and you i have a little neanderthal in us. >> stephen: really? how much? what part of me is neanderthal? is it the guy who comes out when we're drunk? drunk? >> probably, it's in your d.n.a. but it may not be showing physically. >> stephen: is it doing anything in there or is it a sleeper cell, a terrorist d.n.a. sleeper cell? we interbred. >> we did. so basically, we get d.n.a. from the neanderthal fossils and we recreated most of the genome, so comparing that with humans we found people outside of africa people in europe, australia, native americans, they've all got a bit of neanderthal d.n.a. in them. and it's a change of relationship. because i used to think they complete-- we know they didn't go out. their d.n.a. lives on in us. >> stephen